The estimate of the deceleration in the earth's rotation due to the sun

The tidal long-term decrease in the angular velocity of the Earth's rotation has been estimated on the basis of the angular momentum tidal balance in the Earth-Moon-Sun system. The observed (LLR) tidal long-term decrease in the Moon's mean motion, the apparent secular acceleration in the mean longitude of the Sun and the long-term decrease in the 2nd degree zonal geopotential parameter were used.Presented at the XXth General Assembly of the I.A.G., Vienna, August 15, 1991.